Diisocyanates

ABSTRACT

Diisocyanates of the formula:   WHERE N IS 5 TO 20, M IS 0 TO 15, THE SUM OF N AND M IS 14 TO 20, AND R1, R2 and R3 are hydrogen or short chain alkyl groups of 1 to 4 carbon atoms. Polymers prepared from such diisocyanates and organic compounds containing active hydrogens.

[ 51 Sept. 12, 1972 [54] DIISOCYANATES Marwan R. Kamal, Dhahran, Saudi Arabia; Robert C. Kuder, Excelsior,

Minn. 55331 [73 Assignee: General Mills, Inc.

[22] Filed: April 25, 1969 [21] Appl. No.: 819,461

[52] US. Cl. ..260/453 AL, 260/77.5 AT, 260/465.6,

260/584 C [51] Int. Cl ..C07c 119/04 [58] Field of Search ..260/453 AL [56] References Cited UNITED STATES PATENTS 3,455,883 7/1969 Kamal et a1 ..260/453 3,370,077 2/ 1968 Hartzell ..260/453 Primary ExaminerJoseph Rebold Assistant Examiner-C. F. Warren Attorney-Anthony A. .luettner, William C. Babcock and Gene 0. Enockson [57] ABSTRACT Diisocyanates of the formula:

11 ll((llel..( -(Cll:).,.(llgNC() n1 n3 3-( Gll- N( O where n is 5 to 20, m is 0 to 15, the sum ofn and m is 14 to 20, and R R and R are hydrogen or short chain alkyl groups of l to 4 carbon atoms. Polymers prepared from such diisocyanates and organic compounds containing active hydrogens.

8 Claims, No Drawings DIISOCYANATES The present invention relates to new diisocyanates. More particularly, it relates to such diisocyanates derived from diamines prepared by hydrogenating dinitriles ultimately obtained from certain fatty compounds and unsaturated nitriles. It also relates to polymers prepared from such diisocyanates and organic compounds containing two or more active hydrogens.

The new diisocyanates of the present invention have the structural formula:

where n is 5 to 20, m is to 15, the sum ofn and m is 14 to 20, and R R and R are hydrogen or short chain alkyl groups of one to four carbon atoms. R,--R are preferably H. It is especially preferred that the sum of the whole integers n and m is 16. Our new diisocyanates can be reacted with a wide variety of active hydrogen containing compounds to produce polymers including polyurethanes, polyureas and the like. Such polymers are useful as coatings, sealants, adhesives, etc. The diisocyanates of our invention are prepared by the reaction of the corresponding diamines with phosgene. In turn the diamines are prepared by the hydrogenation of dinitriles. The said dinitriles are prepared by the reaction of an a,B-unsaturated nitrile with a hydroxy substituted fatty nitrile. Representative a,B-unsaturated nitriles are acrylonitrile, methacrylonitrile and crotononitrile with the first being the preferred reactant.

The starting hydroxy substituted fatty nitriles can be prepared in a number of ways. One procedure is that set forth in VanderWal Pat. No. 2,558,666 which shows the preparation of mixtures of such starting materials by the reaction of sulfuric acid under moderately low temperatures with unsaturated nitriles to form sulfates (sulfuric esters) which sulfates are then hydrolyzed to form the hydroxy substituted fatty nitriles. Such mixtures can be separated to provide the individual starting hydroxy substituted nitriles.

The preparation of mono-nitriles from fatty acids and ammonia is well known. This preparation and the conditions useful in same are set forth in Fatty Acids And Their Derivatives by A. W. Ralston, 1948, pp. 620-625 (John Wiley & Sons, Inc.). The useful monoethylenically unsaturated aliphatic monobasic carboxylic acids which can be converted to the mononitriles and then to the starting hydroxy substituted mono-nitriles can be represented by the following: 9- hexadecenoic (palmitoleic), 7-hexadecenoic, 2-hexadecenoic, Z-heptadecenoic, 2-octadecenoic, 3-octadecenoic, 4-octadecenoic, 5-octadecenoic, 6-octadecenoic (petroselinic), 7-octadecenoic, 8-octadecenoic, 9-octadecenoic (oleic, elaidic), l0-oc-" tadecenoic, l l-octadecenoic vaccenic), 12-octadecenoic, 2-nonadecenoic, 9-eicosenoic (gadoleic), ll-eicosenoic, l3-docosenoic (erucic), l l-docosenoic (cetoleic) and the like.

The a,B-unsaturated nitrile is condensed with the described hydroxy substituted fatty nitriles using an alintermediate carbamyl chloride by raising the reaction temperature. The reaction is preferably carried out in an organic solvent such as toluene.

The following examples A-F are illustrative of the preparation of the dinitriles and diamines. It is noted that in such examples and the examples of the diisocyanates of the invention to follow, mixtures of position isomers are used and prepared. Such mixtures can be separated such as by chromatography. However, there is ordinarily no reason to do so since the compounds are functionally equivalent.

EXAMPLE A A mixture (140 g., 0.5 mole) of approximately equal parts of 9- and l0-hydroxystearonitrile was heated to C. and 2.5 ml. of catalyst solution (made by dissolving 0.5 g. of sodium in 10 g. of absolute ethanol) was added. Then 26.5 g. (0.5 mole) of acrylonitrile were added and heating was continued for 3 V2 hours at 5164. The reaction-mixture was cooled to 50 C., another 2.5 ml. portion of catalyst solution was added,

' and then 26.5 g. more acrylonitrile was added over a 5- minute period (the temperature increased slightly during this addition). Heating was continued for 3 A hours at 5263 C. After standing overnight at room temperature, the reaction mixture was diluted with 280 ml. of hexane and filtered to remove some insoluble materials assumed to be polyacrylonitrile. The filtrate was washed with equal volumes of l percent by weight aqueous H SO then with saturated salt water containing 2 percent by weight Na CO- then with saturated salt water, and finally with tap water. The washed solution was vacuum-stripped of solvent in a rotary evaporator, leaving 157 g. crude product which was a liquid containing 8.02 percent nitrogen (corresponding to 89 percent cyanoethoxystearonitrile and l 1 percent unreacted hydroxystearonitrile. This product was purified to about percent cyanoethoxystearonitrile by cooling it to 4 C. and filtering off the hydroxystearonitrile which crystallized out. Infrared analysis showed that the product was a mixture of 9- and lO-(B- cyanoethoxy)-stearonitrile. These dinitriles have the formulae:

and

EXAMPLE B Example A is essentially repeated using the mixture of 9- and lO-hydroxy substituted mono-nitriles obtained from palmitoleic acid. The resulting dinitriles have the formulae:

and

EXAMPLE C Example A is essentially repeated using the mixture of lland lZ-hydroxy substituted mono-nitriles obtained from vaccenic acid. The resulting dinitriles have the formulae:

CHa(CHz)e |3-(CH2)9C EN O-CHzCHz-C N and EXAMPLE D A solution of 155 g. of a mixture of 9- and IO-(B- cyanoethoxy)-stearonitrile as prepared in Example A in 150 g. of methanol and 100 ml. of liquid ammonia was hydrogenated over Raney active cobalt catalyst (approximately 23 g.) by heating at l45l48 C. in an autoclave under a hydrogen pressure of l,425-2,l60 psi until no more hydrogen was absorbed (approximately 4 hours). The reaction mixture was then cooled to room temperature, the excess hydrogen and ammonia vented, the catalyst filtered off, and the methanol removed by vacuum-stripping on a rotary evaporator. The crude product was vacuum-distilled to give a colorless liquid boiling at about l65-l75 C. at 0.1 mm. Hg. with an amine number of 315. Infrared analysis showed that the product was a mixture of 9- and l-(y-aminopropoxy)-stearyl amine. These diamines have the formulae:

| O CHzOHqCHzNH:

EXAMPLE E Example D is essentially repeated using the mixture of dinitriles of Example B. The resulting diamines have the formulae:

EXAMPLE F Example D is essentially repeated using the mixture the formulae:

and

The following examples are illustrative of the preparation of the diisocyanates of the invention without being limiting.

EXAMPLE I To a stirred solution of 368 g. of phosgene in 800 ml. of dry toluene was added over a period of one hour a solution of g. of diamine as prepared in Example D in 200 ml. of dry toluene (the reaction temperature, which was initially 15 C., rose to 36 C. during this time). Additional heat was then applied to bring the temperature to 64 C. over a period of 3 hours, while preventing escape of phosgene by means of a reflux condenser cooled to 5 C. The coolant in the reflux condenser was then changed to tap water to allow escape of excess phosgene and of hydrogen chloride while a slow stream of nitrogen was bubbled through the reaction mixture. The temperature of the reaction mixture was increased to ll0 C. over a period of 1 A hours. About one-fourth of the toluene was then distilled off at atmospheric pressure and the remainder under vacuum in a rotary evaporator. The slightly cloudy residual product, amounting to 106 g., was clarified by filtering and then distilled through a falling-film molecular still to give a clear light yellow liquid with a refractive index of l.459(n,, and an NCO content of 19.6 percent. Infrared analysis showed that the product was a mixture of 9- and lO-(y-isocyanatopropoxy)- stearyl isocyanate. These diisocyanates have the form ulae:

EXAMPLE ll Example I is essentially repeated using the mixture of diamines of Example E. The resulting diisocyanates have the formulae:

EXAMPLE in Example I is essentially repeated using the mixture of diamines of Example F. The resulting diisocyanates have the formulae:

CH2CH OH NCO and As indicated above, our new diisocyanates are particularly valuable for the preparation of polymers by reaction with compounds bearing at least two active hydrogen atoms as determined by the Zerewitinoff method. The Zerewitinoff test is described by Kohler in J. Am. Chem. Soc., 49, 3181 (l927). Such polymers are useful especially as coatings for a variety of substrates.

In general, the active hydrogen atoms of compounds reactive with our new diisocyanates are attached to carbon, oxygen, nitrogen or sulfur atoms. Compounds containing the following groups will have active hydrogen atoms: primary amino, secondary amino, carboxyl, diazoamino, hydrazino, hydrazo, hydrazono, hydroxyamino, hydroxyl imido, imino and mercapto. Most often these active hydrogen atoms are attached to oxygen, nitrogen, or sulfur atoms; thus they will be a part of groups such as OH, SH, NH-, -NH CO l-l, CONH -CONHR where R represents an organic radical, SO Ol-l, SO NH and CSNl-l Examples of suitable types of compounds include water, hydrogen sulfide, ammonia, hydroxyl polyesters, polyhydric polyalkylene ethers, polyhydric polythioethers, polyacetals, aliphatic polyols, including alkane, alkene and alkyne diols, triols, tetrols and the like, aliphatic thiols including alkane, alkene and alkyne thios having two or more SH groups; polyamines including both aromatic, aliphatic and heterocyclic diamines, triamine, tetramines and the like; as well as mixtures thereof. Of course, compounds which contain two or more different groups within the above-defined classes may also be used in accordance with the present invention such as, for example, amino alcohols which contain an amino group and a hydroxyl group, amino alcohols which contain two amino groups and one hydroxyl group, aminoacids and the like. Further illustrative classes and specific organic compounds containing active hydrogen atoms useful for preparing polymers according to our invention are described immediately hereinbelow.

Any suitable polyester may be used and may contain terminal hydroxyl groups, terminal carboxylic acid groups, amino groups or the like. Moreover, the polyester may be a polyester amide which was prepared by condensing an amino alcohol containing both free amino groups and free hydroxyl groups with the other components used in the preparation of polyesters. The polyester may be prepared by reacting a polycarboxylic acid or hydroxy carboxylic acid with polyhydric alcohols. It is also possible to use a mixture of polyhydric alcohols and polyamines such as ethylenediamine, polyethylenediamine, l,4-butylenediamine and the like. Amines such as bis-(2-aminoethyl)ether or amino carboxylic acids such as glycine, alanine, valine, phenylalanine, hydroxyproline and the like may also be used. The polyesters may contain hetero atoms in addition to the ester groups including oxygen, sulfur,

' nitrogen and the like in the chain. Moreover, the radicals making up the polyester may be either saturated or unsaturated and may contain double or triple bonds as well as modifying radicals of saturated or unsaturated fatty acids such as oleic acid or fatty alcohols such as oleyl alcohol and the like.

Any suitable polycarboxylic acid may be used in the preparation of the polyesters such as, for example, oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, brassylic acid, maleic acid, fumaric acid, glutaconic acid, alpha-hydromuconic acid, betahydromuconic acid, alpha-butyl-alpha-ethyl-glutaric acid, alpha,beta-diethyl-succinic acid, isophthalic acid, terephthalic acid, hemimellitic acid, trimellitic acid, trimesic acid, mellophanic acid, prehnitic acid, pyromellitic acid, benzenepentacarboxylic acid, l,4- cyclohexanedicarboxylic acid, and the like. Any suitable polyhydric alcohol may be used in the preparation of the polyesters such as, for example, ethylene glycol, l,3-propylene glycol, l,2-propylene glycol, l,4-butylene glycol, l,3-butylene glycol, l,2-butylene glycol, l,5-pentanediol, l,4-pentanediol, l,3-pentanediol, l,6- hexanediol, 1,7-heptanediol, glycerine, trimethylolpropane, l,3,6-hexanetriol, triethanolamine, pentaerythritol, sorbitol and thelike.

Any suitable polyhydric polyalkylene ether may be used as the active hydrogen containing compound such as, for example, the condensation product of an alkylene oxide or of an alkylene oxide with a polyhydric alcohol. Any suitable polyhydric alcohol may be used such as those disclosed above for use in the preparation of the hydroxyl polyesters. Any suitable alkylene oxide may be used such as, for example, ethylene oxide, propylene oxide, butylene oxide, amylene oxide, and the like. Of course, the polyhydric polyalkylene ethers can be prepared from other starting materials such as, for example, tetrahydrofuran, epihalohydrins such as, for example, epichlorohydrin and the like as well as aralkylene oxides such as, for example, styrene oxide and the like. The polyhydric polyalkylene ethers may have either primary or secondary hydroxyl groups and preferably are polyhydric polyalkylene ethers prepared from alkylene oxides having from two to five carbon atoms such as, for example, polyethylene ether glycols, polypropylene ether glycols, polybutylene ether glycols and the like. It is often advantageous to employ some trihydric or higher polyhydric alcohols such as glycerine, trimethylolpropane, pentaerythritol and the like in the preparation of the polyhydric polyalkylene ethers so that some branching exists in the product. Generally speaking, it is advantageous to condense from about 5 to about 30 moles of alkylene oxide per functional group of the trihydric or higher polyhydric 257 to 262, published by lnterscience Publishers, Inc.

(1951), or in U.S. Pat. No. 1,922,459.

Any suitable polyhydric polythioether may be used such as, for example, the condensation product of thiodiglycol or the reaction product of a polyhydric alcohol such as is disclosed above for the preparation of the hydroxyl polyesters with any other suitable thioether glycol. Other suitable polyhydric polythioethers are disclosed in U.S. Pat. Nos. 2,862,972 and 2,900,368.

Any suitable polyhydric alcohol maybe used as the active hydrogen containing compound such as, for example, alkane diols such as, for example, ethylene glycol, l,3-propylene glycol, 1,2-propylene glycol, 1,4- butylene glycol, 1,3-butylene glycol, 1,5-pentanediol, 1,4-butanediol, 1,3-pentanediol, 1,6-hexanediol, 1,7- heptanediol, 2,2-dimethyl-l,3-propanediol, l,8-octanediol and the like including l,20-eicosanediol and the like; alkene diols such as, for example, 2-butenel,4-diol, 2-pentene-l,5-diol, 2-hexene-l,6-diol, 2-heptene-l ,7-diol and the like; alkyne diols such as, for example, 2-butyne-l,4-diol, l,5-hexadiyne-l,6-diol and the like; alkane triols such as, for example, 1,3,6-hexanetriol, 1,3,7-heptane triol, 1,4,8-octane triol, 1,6,12- dodecane trio] and the like; alkene triols such as 4-hexene-l,3,6-triol and the like; alkyne triols such as 2-hexyne-l ,4,6-triol and the like; alkane tetrols such as, for example, l,2,5,6-hexane tetrol and the like; alkene tetrols such as, for example, 3-heptene-l,2,6,7-tetrol and the like; alkyne tetrols such as, for example, 4-octynel ,2,7,8-tetrol and the like.

Any suitable aliphatic thiol including alkane thiols containing two or more -SH groups may be used such as, for example, 1,2-ethane dithiol, 1,2-propane dithiol, 1,3-propane dithiol, 1,6-hexane dithiol, 1,3,6-hexane trithiol and the like; alkene thiols such as for example, Z-butene-l ,4-dithiol and the like; alkyne thiols such as, for example, 3-hexyne-l ,6-dithiol and the like.

Any suitable polyamine may be used including, for example, aromatic polyamines such as, for example, pamino aniline, 1,5-diamino naphthalene, 2,4- diaminotoluene, 1,3,5-benzene triamine, 1,2,3- benzene triamine, l,4,5,8-naphthalene tetramine and the like; aliphatic polyamines such as, for example, ethylenediamine, l,3-propylenediamine, 1,4-butylenediamine, 1,3-butylenediamine, diethylenetriamine, triethylene-tetramine, 1,3,6-hexane triamine, l,3,5,7- heptane tetramine and the like; heterocyclic polyamines such as for example, 2,6-diamino pyridine, 2,4-diamino-S-aminomethyl pyrimidine, 2,5-diamino- 1,3,4-thiadiazole, piperazine and the like.

One especially preferred group of amines useful for preparing polymers according to our invention are polyamines having the primary amine groups thereof blocked by ketimine or aldimine groups. The reaction of carbonyl compounds with the primary amine groups can be illustrated as follows:

The useful carbonyl compounds may have the following theoretical structural formula:

where R and R are organic radicals, are each substantially inert to the ketimine or aldimine formation reaction and are preferably hydrogen or short chain alkyl groups (one to four carbon atoms). Preferred compounds are low molecular weight (C C aldehydes or ketones that are volatile so that an unreacted excess thereof may easily be removed by conventional distillation practices when the reaction is completed. Such volatile compounds are also preferred so that when the blocked polyamine is mixed with the new diisocyanate and exposed to moisture, the freed aldehyde or ketone can be easily removed from the reaction mixture. Examples of preferred carbonyl compounds include such aldehydes and ketones as acetone, methyl ethyl ketone, methyl n-butyl ketone, methyl tert-butyl ketone, ethyl isopropyl ketone, acetaldehyde, propionaldehyde, butyraldehyde, isobutyraldehyde, and the like (i.e. including hexanone and hexanal). The polyamines to be blocked preferably have the structure where R is a difunctional aliphatic group containing from 2-48 carbon atoms, R is an aliphatic group containing 1-24 carbon atoms and n is an integer of from 0-20. Representative R radicals are methyl, propyl, butyl, decyl, hexadecyl, hexanyl octenyl, tridecenyl, octadecyl, undecynyl and the like. lnert or non-interfering groups such as C], nitro and the like may be present on R and/or R Any suitable reaction product of a phenol with an alkylene oxide yielding a compound containing active hydrogens may be used such as, for example, those disclosed in U.S. Pat. No. 2,843,568, such as for example, the reaction product of hydroquinone with ethylene oxide to give a polyalkylene arylene ether glycol having a molecular weight above about 750 or other polyalkylene arylene ether glycols disclosed in said patent.

Any suitable reaction product of a phenol-aldehyde resin with an alkylene oxide may be used such as, for example, a novolac having the formula cm I wherein n is l to 5 and R is a lower alkyl radical such as methyl, ethyl, propyl, butyl, tertiary butyl and the like reacted with an alkylene oxide such as those disclosed above for the preparation of the polyhydric polyalon OH .kylene ethers.

Any suitable reaction product of an amine with an alkylene oxide may be used such as, for example, the I diamine such as 4,4'-diaminodiphenylmethane or the like, xylylene diamine, as well as alkylene diamines such as, for example, ethylenediamine, propylenediamine, 1,4-butylenediamine, hexamethylenediamine and the like including 1,10- dodecane diamine.

Any suitable phenol may be sued such as, for example, 2,2-bis(p-hydroxyphenyl)propane (Bisphenol A) and the like.

Any suitable polyamide may be used such as, for example, those obtained by reacting adipic acid with hexamethylenediamine and the like.

Any suitable polyacetal may be used such as, for example, the reaction product of formaldehyde or other suitable aldehydes with a polyhydric alcohol such as those disclosed above for use in the preparation of the hydroxyl polyester.

Other alcohol compounds which do not necessarily fit within any of the previously set forth classes of compounds and which nevertheless contain active hydrogen containing groups which are quite suitable for the production of the polymers of the present invention are pentaerythritol, sorbitol, triethanolamine, mannitol, N,N,N',N'-tetrakis (2-hydroxypropyl)ethylene-diamine, as well as compounds of any of the classes set forth above which are substituted with halogen such as, for example, chloro, iodo, bromo and the like; nitro; alkoxy, such as, for example, methoxy, ethoxy, propoxy, butoxy and the like; carboalkoxy such as for example, carbomethoxy, carboethoxy and the like; dialkyl amino such as, for example, dimethylamino, diethyl amino, dipropylamino, methylethylamino and the like; mercapto, carbonyl, thiocarbonyl, phosphoryl, phosphato and the like.

Other substances which can be used include natural substances such as castor oil and the like.

The molar proportions of the diisocyanate of our invention and the compounds bearing Zerewitinoff active hydrogen atoms can vary widely. Those skilled in the art can determine the proportions of reactants best suited for a particular purpose. For example, when making polyurethane elastomers, one often uses approximately equimolar amounts of glycol and the new diisocyanate. Preferably, the active hydrogen containing compound will be used in a molar ratio to the new diisocyanate of 1:10 to :1.

The polymers of our invention can be prepared by reacting the new diisocyanate and the active hydrogen containing compound at subatmospheric, atmospheric or superatmospheric pressure. Atmospheric pressure is preferred. The reaction can be operated over a wide range of temperatures. Those skilled in the art will recognize that there are great differences in the relative reactivity of various groups containing active hydrogen atoms, amines reacting faster thartalcohols, primary alcohols reacting faster than tertiary alcoholsto name a few examples; accordingly, one will select a temperature at which the reaction occurs at a rate convenient for the purpose at hand. Preferably, the reaction temperature ranges between about C. and 150 C. However, the temperature is not critical.

If desired, the reaction may be carried out in an inert solvent. Representative solvents include tetrahydrofuran, o-dichlorobenzene, chlorobenzene, xylene, methyl isobutyl ketone, toluene and ethyl acetate. In general, the solvent should be free from isocyanate-reactable groups such as groups bearing Zerewitinoff-active hydrogen atoms.

In the preparation of polymers according to our invention, a portion of the new diisocyanates (i.e. up to about 90 mole percent and preferably from 0 to 50 mole percent) can be replaced by known polyisocyanates. Representative of such known polyisocyanates are ethylenediisocyanate, hexamethylenediisocyanate, butylene-l ,3-diisocyanate, ethylidene diisocyanate, butylidene diisocyanate,

invention are those described in the application of R0- gier and Kamal, Serial No. 250,211, filed January 9, 1963, entitled Polyisocyanates and Derivatives." These polyisocyanates are derived from polymeric fat acids and have the following idealized structural form ula:

R5] [(CH2) NCO:|

where y is O or 1, x is an integer of 2 to about 4 and R is the hydrocarbon groupof polymeric fat acids. Preferably, x is 2. The polyisocyanates of the above formula wherein y is 0 are prepared by converting the polymeric fat acids to the corresponding polymeric acid chlorides, reacting the acid chlorides with a metal azide to form the polymeric acyl azides and then heating the acyl azides to produce the polyisocyanates. The polyisocyanates wherein y is l are prepared by converting the polymeric fat acids to the corresponding polynitriles and then hydrogenating the polynitriles in the presence of ammonia and a catalyst such as Raney nickel to form polyamines. The polyamines are then reacted with phosgene to give the polyisocyanates.

The following examples illustrate the preparation of polymers of the present invention. The said examples are not to be considered as limiting.

EXAMPLE IV A coating composition was prepared by adding 7.4 g. of the diisocyanate as prepared in Example I and 8.1 g. of a ketimine blocked polyamine to 6.6 g. mineral spirits. The ketimine blocked polyamine was prepared by reacting one mole of diethylenetriamine with two moles of methyl isobutyl ketone, the secondary amine group of the polyamine being blocked by reacting the above product with the diisocyanate of Example I in a molar ratio of 2 to 1 to give a compound of the formula:

where R is the residue of the diisocyanate exclusive of the isocyanato groups. Three mil thick coatings of the composition were cast on tin, glass and Carrara white glass. The coatings became tack free in 4-5 hours. After 14 days cure at 70 F. and 50 percent relative humidity, the coatings had these properties: Pencil Hardness on glass 6B; Sward Rocker Hardness on glass 13.3; and G. E. Extensibility on tin 60 percent. After 1,000 hours exposure in a Xenon Arc Weather- Ometer, the coating on Carrara glass had a yellowness of 5.9 (initial 5.0) and 60 gloss reading of 30 (initial 94).

EXAMPLE V Example IV was repeated except that the ketimine blocked polyamine was replaced by 9.5 grams of a 7 compound prepared in the same manner except that The resulting coatings had the following properties: Pencil Hardness on glass 6B; Sward rocker hardness on glass 13.3; G. E. Extensibility on tin 60 percent; yellowness on Carrara glass 6.0 (initial 14.2); and 60 gloss reading on Carrara glass 42 (initial 93).

It is to be understood thatchanges and variations may be made without departing from the spirit and scope of the invention as defined in the appended claims.

. The embodiments of the invention in which an exclusive property or privilege is claimed are defined as lol lows;

l. A diisocyanate having the formula where n is 5 to 20, m is 0 to 15, the sum ofn and m is 14 to 20 and R R and R are hydrogen or alkyl groups of one to four carbon atoms.

he dnsocyanate of claim 1 wherein R R and R R and R3 

2. The diisocyanate of claim 1 wherein R1, R2 and R3 are hydrogen.
 3. The diisocyanate of claim 1 wherein the sum of n and m is
 16. 4. The diisocyanate of claim 1 wherein the sum of n and m is 16 and R1, R2 and R3 are H.
 5. The diisocyanate of claim 1 wherein n is 9 and m is
 7. 6. The diisocyanate of claim 1 wherein n is 8 and m is
 8. 7. The diisocyanate of claim 1 wherein n is 7 and m is
 7. 8. The diisocyanate of claim 5 wherein R1, R2 and R3 are hydrogen. 